On clock faces, 4 is Expressed as IIII, not IV

Original Article ↗ Hacker News Discussion ↗

Historical numeral usage

  • Commenters stress that “IIII” is historically valid Roman notation, not an error.
  • Both additive (IIII, VIIII, XXIIII, etc.) and subtractive (IV, IX, XL) forms coexisted, often mixed even within the same inscription.
  • Evidence cited from coins, classical texts, and monuments suggests subtractive forms existed in Roman times but were not strictly standardized; some say consistent standardization came much later (Middle Ages), but this timing is debated and left unclear.

Aesthetic and design considerations

  • Many argue clockmakers use “IIII” mainly for visual balance and symmetry.
  • Using IIII, V–VIII, and IX–XII yields a pleasing distribution: four numerals with only I, four with V, four with X.
  • Several people note that seeing IV on a dial “looks wrong” simply because IIII has become the conventional aesthetic in horology; it’s widely known as the “watchmaker’s” or “clockmaker’s” four.

Manufacturing and material‑efficiency theories

  • One popular explanation: a single die or plate (e.g., “VIIIIX”) can be stamped four times and cut up to produce all numerals I–XII with minimal waste, which works only if 4 is IIII.
  • Some find this clever and plausible for small workshops; others doubt it yields meaningful savings or matches actual historical manufacturing methods. No consensus emerges.

Legibility and user comprehension

  • Another recurring rationale: with numerals oriented radially, IV near the bottom can be confused with VI when seen upside down or at an angle, especially by semi‑literate viewers reading tower clocks.
  • Critics argue that people know 4 precedes 5 and don’t rely heavily on numerals to read analog time, so this confusion may be overstated.
  • An alternate usability point: IIII is harder to distinguish from III at a glance than IV is, suggesting trade‑offs rather than a clear win.

Religious/taboo and cultural explanations

  • A traditional story holds that IV was avoided because it coincided with an abbreviation of Jupiter’s name, though this is treated more as lore than established fact.
  • Analogies are drawn to Hebrew and Japanese numeral taboos, where certain written forms are altered to avoid sacred or ominous associations.

Roman numerals in modern education and culture

  • Many report minimal or declining instruction in Roman numerals; most exposure now comes from clocks, TV/film copyright dates, the Super Bowl, and Latin classes.
  • Some see value in teaching them briefly to illustrate alternative number systems and “imperfect abstractions”; others view them as low‑priority trivia.
  • Experiences range from teachers insisting IV is the only “correct” 4 to people only later discovering IIII is common and historically grounded.

Related tangents

  • The thread branches into broader discussions of number systems (senary, base‑12, vigesimal French, calendar reforms) and the remarkable longevity and legacy-claims of the Roman Empire, but these are secondary to the clock‑face question.